Luminescent ionic lattice occupation and wide tunable emission spectra of La2MgZrO6:Bi3+,Eu3+ double perovskite phosphors for white light LED

Abstract

La 2 Mg 1– x /2 Zr 1– x /2 O 6 : x Bi 3+ ( x = 0.01–0.035, abbreviated as LMZ:Bi 3+ ) and La 2– y Mg 0.99 Zr 0.99 O 6 :0.02Bi 3+ , y Eu 3+ ( y = 0.1–0.11, abbreviated as LMZ:Bi 3+ ,Eu 3+ ) double-perovskite phosphors were prepared through high-temperature solid-phase method. The emission spectrum of LMZ: x Bi 3+ ( x = 0.01–0.035) phosphors excited at 353 nm is asymmetric in the range between 375 and 650 nm, showing strong green light. There are two luminescent centers of [Mg1/Zr2–O 6 ] and [Mg2/Zr1–O 6 ] for Bi 3+ occupation, which were analyzed through different excitation wavelengths, Gaussian fitting peaks, fluorescence decay curves and Rietveld refinement of powder X-ray diffraction data. Through deep study of the luminescent lattices in the LMZ matrix, the green to blue tunning-emission is observed by different excitation wavelengths. In addition, red emission is obtained by co-doping Bi 3+ /Eu 3+ , and adjustable emission was investigated by changing the content of Eu 3+ in the co-doped phosphor formulation, so it is converted from green emission to red emission. The above results demonstrate how to tune emission color by co-doping rare earth ions in the double perovskite phosphor, which is attractive for future applications. The Gaussian deconvolution of the emission spectrum of LMZ:Bi phosphors was performed to obtain two sub-Gaussian components, and the selective site occupancy of Bi 3+ was analyzed. By co-doping Bi 3+ and Eu 3+ , the luminescence intensity of Eu 3+ can be effectively improved.